Any one running Howards Cams?

Discussion in 'Slant 6 Engines' started by Slantsix64, Aug 1, 2018.

  1. Slantsix64

    Slantsix64 Well-Known Member

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    Camshaft, Mechanical Flat Tappet, Advertised Duration 256/256, Lift .473/.473

    Any ever run this cam? want it with my 64 dodge dart 225 4 speed (3.09) 3.55 gears street car. Trying to balance power and economy
     
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    • xLURKxDOGx

      xLURKxDOGx "An angel fat, at satan's feast"

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      I ran this cam on a 4 speed and it was a blast! Sold the setup to a dude I California who is more than likely enjoying it as well.

      Jake
       
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      • Slantsix64

        Slantsix64 Well-Known Member

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        Cool I will be running this cam with 9.5 compression
         
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        • Slantsix64

          Slantsix64 Well-Known Member

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          Still debating on the Howard's cam 256 duration 220 @.50 473 lift 110

          Or

          the isky 152116 264 duration camshaft 228 @ .50 448 lift 109
           
        • Slantsix64

          Slantsix64 Well-Known Member

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          Howard's operating range is 1800-5600
          isky is 2500-6000

          Howard's will help me keep that low end while the isky looks to be a mid range camshaft.
           
        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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          It's been said that valve lash will take some duration off the advertised, perhaps as much as 10 or more degrees, but it varies with the lashing.
          So It could be possible for the smaller Howards to be a NET of 248*; And the Isky to be a Net of 252*..It would depend on the actual lash. So they could be just 4 degrees apart at advertised.
          But it could go the other way too; say the Howards at 244* and the Isky at 256*. Now 12* apart.
          But it gets worse The advertised does not come with a qualifier such as measured at .006, or .008 or .022; So there is just no telling what you are gonna get until you fingerprint them.
          So, IMO, looking at the advertised, only someone who has installed one and measured it, can say with authority, what the NET advertised worked out to.
          And that just leaves the .050s to work off. In this respect these two cams are just 8* apart, or about 1 cam size. Oh and 1* in the Lsa
          But now look at the lifts. This reveals a lot about the lobes shape. The Howards is .473, and the Isky is .448. I suppose it's possible to put the same rates of acceleration on both lobes. But I suspect the Howards might whack it open faster, such that by .200 it is open further than the Isky, and maybe by .300 still open further. But sooner or later the Howards will have to slow down so as not to fly off when it goes over the top.
          On the other hand, the Isky might open faster and then maintain the rate with a gentle over the top, but averaging more open dwell time.
          Who knows; not me.
          But here's the thing; You have a stated Scr of 9.5 and you have a really long 4.125 stroke, so you are gonna have to be careful to avoid detonation. Sometimes less is more. In this case the earlier intake closing point of the smaller Howards (assuming they are both advertised from the same reference point, and the lash spec is the same), the smaller Howards could NET a larger Scr, and BAM!! put you into detonation..... or require a higher grade of fuel.

          So with that in mind,
          the Howards in at +4* for a 106-ICL gets an ICA of 54*, which after lashing might be 5* less, just guessing, and so we get this
          Static compression ratio of 9.5:1.
          Effective stroke is 3.60 inches.
          Your dynamic compression ratio is 8.42:1 .
          Your dynamic cranking pressure is 172.68 PSI.
          V/P (Volume to Pressure Index) is 102 .

          And the Isky; in at +4 for 105-ICL, and an ICA of 57*, again shrunk 5*, to 52*now
          Static compression ratio of 9.5:1.
          Effective stroke is 3.53 inches.
          Your dynamic compression ratio is 8.27:1 .
          Your dynamic cranking pressure is 168.64 PSI.
          V/P (Volume to Pressure Index) is 97 .

          Ok so the first observation is the excessive cylinder pressures.

          I don't know anything about 225 slantys but I'm pretty sure you can't get gas with a high enough octane rating to suppress detonation at these pressures.
          But let's say for a sec that you could; notice the Howards is making 102VP versus the 97 of the Isky. That works out to plus 5%, and that's a lot, and gives an indication of its ability to perform at low rpm say below 3000, which with a manual trans IMO is almost extremely important.For you with a 3.09 low and 3.55s, this will not be an issue. But when you hit 1.92 second gear it will be. And with 27 inch tires 30mph will be ~2500 in second, so your slanty is gonna need some grunt down there. Yes you could downshift into 3.09 low, but now that split is working against you as the Rs jump up to ~4100 .
          Ok so now, understanding the 1-2 split issue, you gotta pay attention to the lower rpm power production, and the Howards seems to get that done slightly better, if you don't downshift
          But the Isky being 8 degrees larger at .050 will make peak-power about 200 rpm later... so now the downshift sounds pretty good....But that will not help it at 2500 in second.

          But the big thing is gonna be the cylinder pressure. These are both single pattern cams so you can't move them around too far from the camcard spec. You could retard the Isky to match the ICA of the Howards or vice versa, so that's kindof a wash. The overlaps math out to 36 on the Howards, so it's not fussy about a header . The Isky maths out to 46*, so .... BUT again these are solids so the actual nets might be 26 and 36, so that kindof puts the Isky on the fence about wanting a header. Kindof.
          Without knowing more about the durations in the mid lifts, I,personally, at this point, would lean towards the Howards if the 3.55s gotta stay, and also if no header, and also if the 2bbl is staying. Cuz that little wiener 2bbl is gonna be a choke anyway.

          But you gotta do something about the excessive pressure.
          Here is your Howards retarded to 108ICL and an ICA of 56*, shrunk to 51* for lash, with the Scr reduced;
          Static compression ratio of 9.0:1.
          Effective stroke is 3.56 inches.
          Your dynamic compression ratio is 7.90:1 .
          Your dynamic cranking pressure is 158.75 PSI.
          V/P (Volume to Pressure Index) is 92 .
          This would seem to me to be about max-pressure for pumpgas. Your lightweight 64Dart, and small carb might be OK with this. The slightly retarded cam might put your power peak up a few rpm, hard to say for me.
          Ima guessing you shaved the head, so you are gonna have to measure things like; coilbind, retainer interference, and particularly, valve to piston clearance.

          OK one more. Here is the Isky reset to a 108ICL for an ICA of 60*, shrunk to 55* and the compression lowered .
          Static compression ratio of 9.2:1.
          Effective stroke is 3.46 inches.
          Your dynamic compression ratio is 7.88:1 .
          Your dynamic cranking pressure is 158.21 PSI.
          V/P (Volume to Pressure Index) is 89 .
          I like it , but 158psi is still pretty high I really like this install. That 228* cam with the later install, should be good for something like 10 or 12 horsepower even with no header. With as you can see, very little loss in VP. That 2-1 downshift at 30mph should now boogie up to 37/40 or so mph and then the Rs would drop to 3130@37 to 3400@40 yeah I'm liking that. At these rpms that VP thing has shrunk to being almost meaningless.

          So now the issue boils down to reducing your compression,lol.
          What's gonna be easier 9.2 or 9.0..
          Ima thinking that 9.1 and the Isky is your safest bet. Then you cam move the ICA around some for fine-tuning the combo.

          Now keep in mind that I know nothing about 225 slantys and nothing about those cams. Guys feel free to.... kick .... my .... azz .... lol
           
          Last edited: Aug 10, 2018 at 8:22 PM
        • Slantsix64

          Slantsix64 Well-Known Member

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          I guess after re checking my measurements my compression ratio will be 9 to 1 on the dot
           
        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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          BadaBOOM!
           
        • dart19666

          dart19666 FABO Gold Member FABO Gold Member

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        • AJ/FormS

          AJ/FormS 367 FormS clone 3.09-1.92-1.40-1.09-.78od 3.55s

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          logo.gif

          Part Number/Work Order Number F21129
          Engine Application SLANT 6CYL.
          Grind Number 1/4 Race Cam
          ADVERTISED CAMSHAFT SPECIFICATIONS:

          INTAKE: Duration: 240º Lift: .449 Clearance Hot: .020
          EXHAUST: Duration: 244º Lift: .449 Clearance Hot: .022
          The specifications listed above are based on a rocker arm ratio of 1.50 IN/1.50
          Timing Events
          The information below is for degreeing cam only. Correct only at .050" tappet lift.
          INTAKE; Opens: -2.0 ATDC/Closes: 30.0 ABDC
          EXHAUST; Opens: 40.0 BBDC/Closes: -8.0 BTDC
          LOBE SEPARATION 110º
          Duration at .050" :Intake: 208º/Exhaust: 212º
          LOBE LIFT; Intake: .299/Exhaust: .299
          4 degrees of advance have been ground into this Camshaft.

          If using "Lobe Center" method of degreeing, cam should be installed on an intake centerline of: 106º
          NOTES:
          ___________________________________________________________

          Nice cam; but I wonder if it will work in a 9/1 engine. Using their advertised numbers I get an ICA of 46* which I arbitrarily shrunk to 41 for lash allowance, and the Wallace says;
          Static compression ratio of 9.0:1.
          Effective stroke is 3.76 inches.
          Your dynamic compression ratio is 8.29:1 .
          Your dynamic cranking pressure is 169.18 PSI.
          V/P (Volume to Pressure Index) is 104